HttpUrlConnection获取SharePoint Online表单摘要值遇411错误求助

Hey there, I’ve run into similar SharePoint auth quirks before, so let’s break down why you’re hitting that 411 Length Required error even after setting Content-Length: 0.

Key Issues in Your Current Code #

Let’s go through the main problems that are probably causing this:

• Overwriting Cookie Headers
  You’re calling setRequestProperty("Cookie", ...) twice, which replaces the first cookie with the second one instead of combining them. SharePoint needs all the auth cookies sent in a single Cookie header, separated by semicolons.

• Incorrect Accept Header
  The Accept header is set to application/x-www-form-urlencoded, but SharePoint’s /_api/contextinfo endpoint returns either XML or JSON. This mismatch can throw off the server’s response handling.

• Unwritten Output Stream
  When you set setDoOutput(true), HttpURLConnection expects you to write something to the output stream—even if it’s empty. Just setting Content-Length: 0 isn’t always enough; you need to explicitly open and close the stream to signal the request is complete.

Revised Code with Fixes #

Here’s your code updated with these fixes applied, with comments highlighting changes:

public String getFormDigestValue(List<String> cookies) throws IOException {
    URL u = new URL("https://xxx.sharepoint.com/_api/contextinfo");
    HttpURLConnection connection = (HttpURLConnection) u.openConnection();
    
    connection.setRequestMethod("POST");
    connection.setDoInput(true);
    connection.setDoOutput(true);
    connection.setInstanceFollowRedirects(false);
    
    // Fix 1: Use an appropriate Accept header for SharePoint's API
    connection.addRequestProperty("Accept", "application/xml;odata=verbose");
    connection.addRequestProperty("Content-Type", "text/xml; charset=utf-8");
    
    // Fix 2: Combine cookies into a single header instead of overwriting
    String combinedCookies = cookies.get(1) + "; " + cookies.get(2);
    connection.setRequestProperty("Cookie", combinedCookies);
    
    connection.setRequestProperty("Origin", "https://xxx.sharepoint.com"); // Added https:// for validity
    
    // Fix 3: Explicitly handle the empty output stream
    connection.setFixedLengthStreamingMode(0); // Ensures Content-Length is properly set
    try (OutputStream out = connection.getOutputStream()) {
        // Write nothing, just close the stream to complete the request
        out.flush();
    }
    
    // Read the response
    try (InputStream in = connection.getInputStream()) {
        StringBuilder sb = new StringBuilder();
        int c;
        while ((c = in.read()) != -1) {
            sb.append((char) c);
        }
        String result = sb.toString();
        
        String startTag = "<d:FormDigestValue>";
        String endTag = "</d:FormDigestValue>";
        
        if (!(result.contains(startTag)) || !(result.contains(endTag))) {
            throw new IOException("Error during getting form digest value: Value missing in response.");
        } else {
            int startIndex = result.indexOf(startTag);
            int endIndex = result.indexOf(endTag, startIndex + startTag.length());
            return result.substring(startIndex + startTag.length(), endIndex);
        }
    }
}

Why This Works #

• Combined Cookies: SharePoint receives all necessary auth cookies in one header, so it recognizes your authenticated session.
• Correct Accept Header: The server returns a response format your code can parse, avoiding unexpected handling.
• Explicit Output Stream Handling: By opening and flushing the empty output stream, you signal to HttpURLConnection that the request body is complete, which resolves the 411 error.

Why Postman Works #

Postman automatically handles small details like combining cookies from your session, setting appropriate headers, and properly sending empty request bodies—things that HttpURLConnection requires you to handle manually.

内容的提问来源于stack exchange，提问作者Петър Петров